Rajmond Jano

Accelerated ageing tests for predicting capacitor lifetimes

Being reliability critical components, and widely used in electronics today, electrolytic aluminum capacitors are one of the most likely components to fail under extreme working conditions. Therefore in safety critical applications, their lifetime prediction is of vital importance. The following paper analyses current prediction algorithms and offers an improved solution for capacitor lifetime prediction. The results are obtained from accelerated ageing tests and theoretical data obtained from calculi are compared to real world data obtained from measurements.

Parameter monitoring of electronic circuits for reliability prediction and failure analysis

As electronic modules are becoming ever more popular in critical safety applications, such as electronic vehicles and aeronautics, so do their operating conditions become harsher. This sometimes means using electronic components at the very limit of their functional parameters and very close to or even exceeding their maximum operating temperature. This of course leads to a dramatic decrease in component lifetimes and classical failure prediction algorithms are thrown off balance, giving unreliable results. This of course means that new prediction methods should be established. The following paper proposes a method for predicting the value of capacitors on the electronic modules, in order to perform real-time prediction of their lifetimes affected by their operational environment. First, two capacitor lifetime models are presented and compared and then the theoretical data are compared with the data obtained from accelerated ageing measurements.

Effects of reflow soldering methods on the lifetime of capacitors

The influences of different soldering methods and specific thermal profiles were investigated on the lifetime of through hole capacitors. The behavior of aluminum electrolytic, ceramic and two capacitor types with different plastic dielectric capacitors were evaluated when using alternative soldering methods instead of the standard wave soldering process, such as vapour phase or infrared convection. The changes in the values of capacitance and ESR of the capacitors were monitored before and after soldering and the influence of the different techniques on their lifetimes was assessed.

Soldering profile optimization for through-hole and surface mounted ceramic capacitors

The paper examines the feasibility of using vapour phase or infrared reflow soldering technologies for multi-layer ceramic chip (MLCC) and disk ceramic capacitors by employing the pin-in-paste technology. During practical experiments recommendations are made for optimizing the thermal profiles used when soldering there types of components in order to minimize the drift in the capacitance and ESR values of these types of capacitors.

Investigations of thermal influences on clock speed of embedded devices

This paper analyses the influence of temperature of the CPU of an embedded device, mainly on the application execution time. The study is performed on an AtMega8L microcontroller, placed in a thermal chamber, where different temperatures were set, to show how increasing the temperature can affect the microcontroller speed. Also, several speed configurations were built, using oscillators of 1MHz and 4MHz (internal oscillator) and 4MHz external crystal, in order to better observe the behavior of the studied device. Through experimental work, it has been shown that some configurations are more stable and can be used successfully in most extreme conditions.

Implementation of a car model for indirect tire pressure monitoring system

The main purpose of this paper is to present a software implementation referring to an indirect Tire Pressure Measurement System (iTPMS) based on the Anti-lock Braking System (ABS) present in a car. The novelty of the research is the achievement of a Simulink car model which is able to feed simulated data consistent with real-life measurements to the hardware system for functional testing of the implemented measurement method, without the need of an actual car and road test. An additional Android application is implemented for the purpose of helping the driver to determine and solve the problem stated by the possibility of appearance of tire under inflation.

Thermal management of System-on-Chip devices used in satellite systems under low temperature conditions

The lifetime and performances of integrated circuits are strongly influenced by temperature conditions. In the vacuum of space, the temperature of objects can vary considerably depending on their position relative to the sun. Over the years, many advanced cooling techniques have been developed for integrated systems affected by temperature increases above their operating temperature. The purpose of this paper is to study the endurance at low temperatures of a System on Chip (SoC) based device placed in a satellite orbiting around the Earth and also to design a heating solution to sustain the device. In order to maintain the integrated components functional when the satellite is located in Earths shadow, a heating solution was developed by sizing and positioning a heat dissipating track integrated within the inner layer of the PCB. The heating solution takes into consideration the most sensitive component on the PCB, the QFN chip with a thermal pad. The temperature at which the system must be brought is minimum 0°C considering an environmental temperature of -100°C. The designed solution is thermally simulated based on different scenarios.

Simulation and educational tool for fault modelling in logic circuits

Teaching electronic engineering and keeping students interested may sometimes be a challenge, especially for phenomena that rely heavily on a theoretical background. Classical SPICE simulators, although excellent at offering accurate results, rarely offer explanations as to how those results are obtained. This paper presents a novel simulator for modelling logic circuit faults implemented in MathWorks MATLAB which aims not only to provide correct waveforms for the simulated faults, but also let students understand how those results were obtained and what impact they would have in a real-life application of the circuit.

Task allocation for thermal optimization in multicore systems

Power dissipation for processors used in personal computers evolved along the evolution of processor capabilities. Datasheets normally contain the thermal design power (TDP), which is the maximum amount of heat generated by the CPU, which the cooling system in a computer is required to dissipate. The current research above aims to bring a decrease in the total power consumption of a processor, thus decreasing the temperature of the whole computing system, by proposing a task allocation method for multicore systems.

Guidelines on thermal management solutions for modern packaging technologies - a review

Thermal management for modern electronic systems can follow two fundamental paths: one concentrates design efforts towards low power/high efficiency electronic circuits/components, the other implies, where the previous one reaches its limits, optimizing thermal transfer in the entire system at chip level, package level, and PCB/assembly level. Thus, exploring all methods of improving heat transfer at chip/package/assembly levels can generate a guideline for common/specific approach that can be used at the earliest stage of a design. The current research gives an overview of latest packaging technology along with required thermal management measures and proposes a consistent methodology of Design for Thermal Management.